The present invention relates to treatment fluids comprising magnetic surfactants and methods relating thereto.
Viscosified treatment fluids are useful in a variety of subterranean operations including those that transport particles like drill cuttings, proppants, and gravel. Increasing the viscosity of a fluid is typically achieved through the use of viscosifying agents like clays, polymers, and crosslinked polymers. As used herein, “treatment fluid” refers to any fluid that may be used in a subterranean application in conjunction with a desired function and/or for a desired purpose (i.e., any “treatment”). The terms “treatment” and “treatment fluid” do not imply any particular action and encompass, inter alia, drilling fluids, lost circulation fluids, fracturing fluids, acidizing fluids, and the like.
In some cases during drilling, completing, or remediating a subterranean well, it is desirable to have a fluid with viscosity and apparent density that can be temporarily increased by the application of a suitable magnetic field. The localized high magnetic viscosity will temporarily separate different portions of a fluid system. In the case of a flowing fluid system, a localized magnetic viscosity increase can throttle the flow, increasing the pressure drop in that section to slow the flow or increase the pressure in the system. More specifically, it may be desirable to replace or augment the mechanical valve or “choke” that controls the return flow of drilling fluid for Managed Pressure Drilling.
Magneto-rheological additives like ferromagnetic particles have been investigated as an alternative to or augmentation of viscosifying agents. It is believed that ferromagnetic particles respond to the application of a magnetic field by aligning, and thereby increasing the apparent viscosity of a fluid. Upon removal of the magnetic field, the ferromagnetic particles redisperse and the viscosity of the fluid decreases. Some ferromagnetic particles are responsive to the strength of the magnetic field thereby allowing for tuning the viscosity of the fluid.
However, the use of ferromagnetic particles in subterranean applications has been limited because of their expense in combination with the amount needed for a single treatment operation in a subterranean formation. Another barrier to application may be that ferromagnetic particles can change the density of the treatment fluid at ambient conditions, which does not allow for a simple add-in technology.